Fluid camomile extracts may be obtained in various ways, for example by maceration, percolation, repercolation, or chain percolation. One feature common to all these processes is that the starting material used is the camomile drug, i.e. the dried flowerheads. The quality of camomile flowers and camomile extracts depends not only on the bisabolol content, but also on the contents of ethereal oil, chamazulene and flavones.
The camomile flowers lose 75 to 85% of their weight in the drying process. At the same time, however, the flowers also lose active substances to an extent which depends upon the type of drying process used. In the drying of fresh camomile of the bisabolol type under production conditions, a loss of 47a% of essential oil or rather 48% of chamazulene and 46% of (-)-.alpha.-bisabolol can be expected to occur, for example even at relatively low drying temperatures.
Further losses of active substance occur during storage of the camomile drug. For example, after storage of the camomile drug for 1 year, the essential oil content decreased by 43.8%, the chamazulene content of the essential oil decreasing over proportionally by 68.4%.
Another problem is that the active substances present in the camomile are very difficult to extract from the drug. For example, in the production of fluid extracts with 45% alcohol, ony about half the essential oil in the drug passes over into the extract.
The extraction of fresh camomile (i.e. freshly harvested flowerheads) has not yet been carried out because freshly harvested plants or parts thereof undergo numerous enzymatically controlled or microbially induced processes which affect their contents. It is only through removal of the water during drying that the vegetable enzymes are inactivated or rather denatured. There has only been one reported case (Arch. Phar. 280 (1942), pages 437-38) where fresh camomile is extracted with 86% alcohol, although the extract has to be subsequently boiled for 20 minutes to destroy the enzymes. In this case, however, the azulene yield was only 18.4% and, after only 5 months, the extract had lost virtually all the azulene originally present.
In addition, the active substances in known comamile extracts have only a limited storage life. In particular, there is a rapid reduction in the chamazulene content which cannot be prevented even by addition of alkali.
It has now surprisingly been found that the extraction of fresh camomile in accordance with the present invention has advantages over the known extraction of the camomile drug. In particular, it is possible to improve the yield of active substances and also their storage life.